Electric Condiment Grinder with Epicyclic Geartrain

ABSTRACT

A grinder for condiments such as pepper has a grinding rotor mounted to rotate relative to a grinding stator for grinding the condiment therebetween. An speed-reducing epicyclic geartrain is connected for transmitting torque between a motor and the rotor. The geartrain includes a plurality of spur gear epicyclic gearsets, each gearset comprising planet gears meshed with a sun gear, the planet gears of each gearset supported upon a planet carrier, the gearsets stacked within a common ring gear with the sun gears coaxial, adjacent sun gears and planet carriers of adjacent gearsets being rotationally fast for transmitting torque between the adjacent gearsets. The adjacent sun gears and planet carriers of adjacent gearsets are integrally formed a melt processable polymer. The gearsets are held between an end wall and a closure at axially opposing ends of the ring gear to form a gearbox, the end wall being formed integrally with the ring gear and the closure being fixed to the ring gear.

TECHNICAL FIELD

The present invention relates to grinders for condiments such as pepperor salt, and particularly to grinders driven by electric motors throughan epicyclic geartrain.

BACKGROUND OF THE INVENTION

Hand-held cordless electric grinders provide a convenient and fastmethod for dispensing freshly ground peppers or the like. A conventionalgrinder of this type has a battery compartment at the top of thehousing, with an electric motor connected via a speed reductiongeartrain to a drive shaft. The geartrain includes heavy metal gearswith high tooth loadings. The shaft extends through a condimentreservoir to a grinding mechanism at the base of the housing.

Whereas the art is replete with various designs of condiment grinders,it will be understood that there is nevertheless a continuing need forand interest in improvements to electric condiment grinders of thistype. In particular there is a need for designs that are able to bemanufactured more cost-effectively. The grinder should have a geartrainwith a low weight and inertia and which can be readily installed. Itshould also be compact with coaxial drive and driven shafts, relativelyefficient and quiet in operation, while being able to operate at highmotor speeds. It is an object of the present invention to address theabove needs or more generally to provide an improved condiment grinder.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided acondiment grinder comprising:

a motor having a motor shaft that rotates about a central axis;a grinding rotor mounted to rotate about the central axis relative to agrinding stator, the rotor and stator cooperating for grinding thecondiment therebetween, anda plurality of spur gear epicyclic gearsets connected for transmittingtorque from the motor shaft to the grinding rotor, each gearsetcomprising planet gears meshed with a sun gear, the planet gears of eachgearset supported upon a planet carrier, the gearsets stacked within acommon ring gear with the sun gears coaxial, adjacent sun gears andplanet carriers of adjacent gearsets being rotationally fast fortransmitting torque between the adjacent gearsets.

Preferably the gearsets are formed from a melt processable polymer, theadjacent sun gears and planet carriers of adjacent gearsets beingintegrally formed, the planet carriers having a disc portion with firstand second opposing parallel faces extending perpendicular to thecentral axis, a plurality of axle portions protruding from the firstface for supporting planet gears, the sun gear protruding from thesecond face.

Preferably the gearsets are held between an end wail and a closure ataxially opposing ends of the ring gear to form a gearbox, the end wallbeing formed integrally with the ring gear and the closure being fixedto the ring gear.

Preferably the grinder further comprises a housing having abattery-receiving compartment in an upper portion thereof, a condimentreservoir in a lower portion of the housing adjacent the grinding rotorand stator, an intermediate compartment between the condiment reservoirand battery compartment, a pair of coupling parts receiving the motorand gearbox, the coupling parts being joined to form a module in whichthe motor and gearbox are in drivingly connected, at least one of thecoupling parts having a jaw slidably mounted thereto for movementbetween an extended position in which the jaw extends from an outersurface of the at least one coupling part to be received in a recess inthe housing for holding the module in position within the intermediatecompartment; and a retracted position in which the jaw is retractedwithin the outer surface.

Both of the coupling parts are preferably hollow, said at least one ofthe coupling parts including two jaws mounted to slide betweenrespective retracted and extended positions, the jaws being received toslide radially within respective laterally-extending openings ondiametrically opposite sides of said at least one of the coupling parts.

This invention provides a grinder which is effective and efficient inoperational use, and which may be economically constructed. It has ageartrain with a low weight and inertia, which is compact with coaxialdrive and driven shafts, is relatively efficient and quiet in operation,and is able to operate at high motor speeds. It also simplifies assemblyand maintenance by offering an essentially modular design.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described by way ofexample with reference to the accompanying drawings, wherein:

FIG. 1 is a central longitudinal cross section a preferred embodiment ofthe grinder of the invention;

FIG. 2 is an exploded view of the geartrain and motor assembly of thegrinder of FIG. 1

FIG. 3 is schematic of the geartrain of the grinder of FIG. 1, and

FIG. 4 is a transverse cross section along line AA of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, a hand-held cordless electric grinderincludes a housing 1 having a generally circular cross section of awaisted form, having broader dimensions near its base and top. A batterycompartment 2 is provided at the top of the housing above an electricmotor 3 having a shaft 5 rotating about the central axis 4. The motorshaft 5 is connected through an epicyclic geartrain to the inner end ofelongate drive shaft 7 extending through a condiment-receiving reservoir8. The motor 3 and epicyclic geartrain are received in the waistedportion of the housing within an intermediate compartment between thebattery compartment 2 and condiment reservoir 8. The outer end of theshaft is rotationally fast with grinding rotor 9 which cooperates with agrinding stator 10 for grinding the condiment therebetween.

The epicyclic geartrain module or gearbox 31 includes four spur gearepicyclic gearsets 11-14 mounted coaxially. The elements of the gearsetsare moulded from a melt processable polymer. Each of the gearsets 11-14comprises planet gears P1 P2, P3, P4 meshed with a respective sun gearS1, S2, S3, S4 and supported upon a planet carrier C1, C2, C3, C4. Theplanet carriers C2, C3, C4 are of common construction, each integrallyformed and rotationally fast with a respective one of the sun gears S1,S2, S3. The gearsets 11-14 are stacked within a common ring gear R, withwhich all the planet gears P1, P2, P3, P4 mesh.

The carrier C1 includes three parallel, equally angularly spaced shafts15-17 for supporting the three planet gears P1. The carriers C2, C3, C4also include like shafts 15-17, and further include a shaft 18diametrically opposite shaft 15, together with two tabs 19 positioned tobalance the mass of the shaft 18. The carriers C1, C2, C3, C4 include adisc portion 50 with a radially-extending face 20 from which the shafts15-17 protrude, and an opposing parallel face 21. The planet gears P1,P2, P3, P4 also include parallel opposing radially-extending surfaces22, 23.

Formed integrally with the ring gear R at Its outer end is an end wall51 forming a shoulder abutting the outer face 21 of the carrier C1 forlocating the carrier C1 axially. The gearsets 11-14 are stacked axiallywithin the ring gear R, the three planet gears P1, P2, P3 being mountedon the shafts 15, 16, 17 and located axially without the need forfasteners, or the like, being received between faces 20 and 21 of theadjacent carriers.

A closure 24 includes an annular flange 26 which is received in acomplementary recess 27 formed in the outer wall of the ring gear R. Aninterference fit between the flange 26 and recess 27 prevents movementof the closure 24 relative to the ring gear R. The closure 24 includesan end wall 25 retaining the gearsets 11-14 within the ring gear R. Thetwo planet gears P4 are mounted on the shafts 15 and 18 and axiallylocated between the face 20 of the carrier C4 and the end wall 25.Formed on the upper side of the end wall 25 are protrusions 29 receivedin respective recesses 30 in the motor 3 to prevent rotation between thering gear R and motor 3.

The epicyclic gearbox 31 and electric motor 3 are assembled as a drivemodule 41 within upper and lower hollow coupling parts 32, 33, receivingthe motor 3 and gearbox 31 respectively. The coupling parts 32, 33 haveaxially aligned cylindrical walls 39, 40 and are coupled by engagementof the annular rim 34 of the upper coupling part 32 received in themouth 35 of the lower coupling part 33, the coupling parts 32, 33 thenbeing permanently joined as by adhesive, welding or the like. Receivedto slide radially within respective laterally-extending openings 36 ondiametrically opposite sides of the lower coupling part 33 are two jaws37, each having a head 38. The jaws 37 are extended such that each head38 projects from the surface 40 and is received in a recess 52, therebylocating the drive module 41 within the housing 1.

A battery holder 43 is supported on the upper coupling part 32. Thebattery holder 43 includes circumferentially spaced cavities 44, eachreceiving a generally cylindrical battery cell (not shown).

A coupler 45 transmits torque from the carrier C1 to the shaft 7. Theshaft 7 has a square cross section and the lower end 48 of the couplerhas a complementary opening. The upper end 47 includes axially elongatedribs and is received in a recess (not shown) of complementary shape inthe carrier C1. The coupler further includes an annular face 46. A seal49 is received in a groove in the lower coupling part 33 extending aboutthe coupler 45, with the seal 49 engaging the annular face 46.

Aspects of the present invention have been described by way of exampleonly and it should be appreciated that modifications and additions maybe made thereto without departing from the scope thereof.

1. A condiment grinder comprising: a motor having a motor shaft thatrotates about a central axis; a grinding rotor mounted to rotate aboutthe central axis relative to a grinding stator, the rotor and statorcooperating for grinding the condiment therebetween, and a plurality ofspur gear epicyclic gearsets connected for transmitting torque from themotor shaft to the grinding rotor, each gearset comprising planet gearsmeshed with a sun gear, the planet gears of each gearset supported upona planet carrier, the gearsets stacked within a common ring gear withthe sun gears coaxial, adjacent sun gears and planet carriers ofadjacent gearsets being rotationally fast for transmitting torquebetween the adjacent gearsets.
 2. The grinder of claim 1 wherein thegearsets are formed from a melt processable polymer, the adjacent sungears and planet carriers of adjacent gearsets being integral, theplanet carriers having a disc portion with first and second opposingparallel faces extending perpendicular to the central axis, a pluralityof axle portions protruding from the first face for supporting planetgears, the sun gear protruding from the second face.
 3. The grinder ofclaim 2 wherein the gearsets are held between an end wall and a closureat axially opposing ends of the ring gear to form a gearbox, the endwall being formed integrally with the ring gear and the closure beingfixed to the ring gear.
 4. The grinder of claim 3 wherein the grinderfurther comprises a housing having a battery-receiving compartment in anupper portion thereof, a condiment reservoir in a lower portion of thehousing adjacent the grinding rotor and stator, an intermediatecompartment between the condiment reservoir and battery compartment, apair of coupling parts receiving the motor and gearbox, the couplingparts being joined to form a module in which the motor and gearbox arein drivingly connected, at least one of the coupling parts having a jawslidably mounted thereto for movement between an extended position inwhich the jaw extends from an outer surface of the at least one couplingpart to be received in a recess in the housing for holding the module inposition within the Intermediate compartment; and a retracted positionin which the jaw is retracted within the outer surface.
 5. The grinderof claim 4 wherein both of the coupling parts are hollow, said at leastone of the coupling parts including two jaws mounted to slide betweenrespective retracted and extended positions, the jaws being received toslide radially within respective laterally-extending openings ondiametrically opposite sides of said at least one of the coupling parts.